This invention relates to a regulator and shut-off valve assembly of the cartridge type as conventionally used in water coolers to control the flow of water from a source to the outlet or spigot. The valve assembly includes a hollow cylindrical body which is received in a complemental bore formed in a casting which is a part of the cooler. When in place, the valve assembly connects a source of water under pressure to the outlet or spigot of the water cooler through inlet and outlet passages and a valve-controlled opening in the inlet passage. The opening usually is coaxial with the body of the assembly and faces inwardly while a valve opposes the opening and is movable toward and away from the latter. The valve is carried by a stem which extends along the axis of the body and is movable longitudinally to move the valve. The valve stem is depressed manually to move the valve away from the opening and is returned to its original position by a spring. Customarily, the principal parts of the valve assembly are molded from a semi-rigid plastic material and typical assembly of this type is shown in Turner et al U.S. Pat. No. 3,902,600. In prior assemblies of this type, there has been a tendency of the valved opening to shift or creep relative to the valve, especially when the parts are made of plastic, and such creeping can interfere with the proper cooperation of the valve and the opening.